An image forming apparatus, to which a plurality of cartridges are detachably mountable, with the cartridges each having a cartridge side identification portion, includes an image forming unit configured to form an image, a plurality of mounting portions to which the cartridges are demountably mountable, and an identification urging mechanism provided in each of the mounting portions. The identification urging mechanism permits a cartridge to be mounted to the mounting portion when the cartridge is to be properly mounted to the mounting portion on the basis of correspondence with the cartridge side identification portion, and urges the cartridge in a direction opposite a direction in which the cartridge is mounted when the cartridge is improper for the mounting portion. The identification urging mechanism permits, even when the cartridge is improper for the mounting portion, the cartridge to enter to a mount position where the proper cartridge is mounted.